1. Field of the Invention
The present invention relates to a magnetic-anisotropic plastically deformed body, which is plastically deformed but exhibits a magnetic anisotropy, a method for producing the same, and an electromagnetic apparatus using the same.
2. Description of the Related Art
An electromagnetic valve, which is one of electromagnetic apparatuses, has an electromagnetic coil (solenoid), and fixed and movable cores. The fixed and movable cores each contain a soft magnetic substance, and are magnetized and demagnetized depending on an electromagnetic action of the electromagnetic coil. When the electromagnetic coil is energized to generate a magnetic field, the fixed and movable cores are magnetized, whereby a valve element disposed on the movable core is displaced, and then the electromagnetic valve of a normally closed type is opened, and the electromagnetic valve of a normally open type is closed. When the energization is stopped to eliminate the magnetic field, the fixed and movable cores are demagnetized, whereby the valve element returns to the original position, and then the electromagnetic valve of the normally closed type is closed, and the electromagnetic valve of a normally open type is opened.
In the electromagnetic valve having such a structure, there is a demand for reducing the time from the start until the end of the open/close operation, i.e. for increasing the response speed, after the switching from the energized state to the energization stop state or from the energization stop state to the energized state. This demand may be satisfied by controlling a magnetic flux flow in the magnetization of the fixed or movable core.
From this viewpoint, Japanese Laid-Open Patent Publication No. 11-108231 proposes a pseudo-rod-like body, which is formed by radially arranging a plurality of unidirectional electromagnetic steel sheets on a base made of an electromagnetic steel sheet having a predetermined shape. However, the unidirectional electromagnetic steel sheets have flat plate shapes as indicated by the name, so that a difficult complicated procedure is required for radially arranging the sheets. Furthermore, the unidirectional electromagnetic steel sheets are expensive, resulting in high cost.
Furthermore, it is necessary to process the base into a predetermined shape suitable for the flat plate shapes of the unidirectional electromagnetic steel sheets. Also, this processing results in high cost.
In addition, the unidirectional electromagnetic steel sheets and the base of the electromagnetic steel sheet cannot be bonded with a sufficient adhesion force by an adhesive. Therefore, the pseudo-rod-like body may exhibit an insufficient durability against application of an impact load on the adhesive in the open/close operation.
Japanese Laid-Open Patent Publication No. 10-158741 proposes that, in a recrystallization treatment after a heavily cold rolling process, a magnetic field is applied parallel to the rolling direction to improve the magnetic property of the unidirectional electromagnetic steel sheet. However, this procedure can be used only for such a flat plate-shaped member, and thus a product cannot be obtained with a shape other than the flat plate shape. Consequently, the above problems cannot be solved by this procedure.